Valtrex lowered both viruses in
female genital tract, study found
By E.J. Mundell HealthDay Reporter
Treatment with valacyclovir (Valtrex) or a cheaper herpes antiviral,
acyclovir, could also reduce HIV transmission during sexual intercourse, say
international researchers who conducted the trial in Africa.
“Our results open a new avenue and raise hopes for HIV control (both
prevention and care) in a period where new tools are desperately needed,” said
lead researcher Dr. Nicolas Nagot, an epidemiologist at the
London School of Hygiene and Tropical Medicine.
The findings are published in the Feb. 22 issue of the New England Journal of
AIDS experts have long recognized the deadly partnership
between the herpes simplex virus (HSV) and HIV.
“You can imagine that if you have genital herpes, the ulcers that are
associated with that could act as a direct gateway through which the HIV could
travel,” explained Dr. Rowena Johnston, vice president of research at the
Foundation for AIDS Research (amfAR), based in New York City.
Furthermore, active genital herpes infection, whether symptomatic or
asymptomatic, causes the body’s immune system to send a rush of activated
T-cells to the area of herpes activity. “Once these cells are activated and busy
trying to find the herpes, their activation means that they are in the exact
state they need to be in for HIV to infect them,” explained Johnston.
On the flip side, HIV can debilitate the immune system and thereby encourage
herpes flare-ups, said another infectious disease expert, Dr. Philip Keiser, of
the University of Texas Southwestern Medical Center in Dallas.
“The number of outbreaks of HSV in someone who is HIV are much higher,” he
said. “So, the two viruses are clearly co-factors; they both stimulate each
In some African countries, the problem is compounded by
the fact that more than 60 percent of adults are thought to be infected with the
herpes virus, Johnston said. By contrast, the U.S. rate of genital herpes infection is about
one in five, according to the U.S. Centers for Disease Control and Prevention.
All of this suggests that interventions that control HSV might also help
Nagot’s team conducted a randomized, double-blinded, placebo-controlled
trial involving 140 women from the West African nation of Burkina Faso, all of
whom tested positive for both HIV, the virus that causes AIDS, and HSV-2, the
herpes strain most often linked to genital infection.
The patients — who were for various reasons ineligible
for antiretroviral HIV-suppressing drugs at the time of the study — received
either 500 milligrams of HSV-suppressing Valtrex twice daily or a placebo for 12 weeks. The
researchers then tracked the women for three months of follow-up.
They found that use of Valtrex cut down the amount of
time HIV was highly present and active in the genital tract — “shedding” — by
59 percent, on average, and significantly reduced HIV viral load — both within the female
genital tract and in the bloodstream.
For the first time, the study proves in a clinical
setting, “that HIV replication is causally related (at least in part) to HSV replication; and we
have demonstrated that this replication can be reduced (in the genital fluids
and plasma) with an
antiviral therapy that is only directed at HSV-2,” said
study senior researcher Dr. Philippe Mayaud, also of the London School of
Hygiene and Tropical Medicine.
Herpes treatment could never offer full protection against HIV, the
researchers stressed. However, by lowering levels of HIV within the genital
tract, it may reduce sexual transmission of the virus.
Furthermore, by lowering blood levels of HIV, herpes treatment should bolster
patients’ immune systems and thus “prolong the time until [they] need to start
antiretroviral therapy,” Mayaud said.
Valtrex, which remains under patent to maker GlaxoSmithKline, might still be
too expensive for widespread use in developing countries. But the study’s
authors said another generic drug, acyclovir, is showing similar promise and is
The Burkina Faso trial was too short to show any Valtrex-linked reductions in
HIV-related symptoms or illness in the women, Mayaud said. “The logical next
step is to study the effect of acyclovir or valcyclovir over a longer duration,
to study the impact on HIV-related outcomes linked to disease progression, like
the decline in CD4 [T-cell] counts,” he said.
The study also raises the intriguing possibility that a herpes vaccine might
help control HIV transmission, too.
So far, efforts to develop a 100-percent effective HSV vaccine have failed,
Nagot said. But immunization, “even if imperfect at preventing acquisition of
HSV, might have a great public health impact at decreasing HSV shedding and
indirectly at preventing acquisition or transmission of HIV,” he said. “We hope
our research (and that of others that will follow) will reinvigorate this
For now, getting inexpensive HSV-suppressing medications to people infected
with both herpes and HIV seems reasonable, the experts said.
“Certainly for women, if they have evidence of HIV, this argues that you
should give them something to suppress their HSV along with the HIV, and keep
them on it routinely,” said Keiser. He noted that Valtrex has a very good
side-effect profile, even over the long term.
And Johnston said the study reinforces an important lesson.
“You come to the realization that dealing with HIV is not necessarily about
dealing with HIV alone,” she said. “Treating herpes is really a very important
step towards trying to reduce the overall global burden of HIV, because we know
that HSV is such a significant risk factor for getting HIV and transmitting it.”
Find out more about the fight against HIV/AIDS at amfAR.
SOURCES: Nicolas Nagot, M.D., epidemiologist, and
Philippe Mayaud, M.D., reader, infectious disease and reproductive health, both
of the London School of Hygiene and Tropical Medicine, U.K.; Rowena Johnston,
M.D., vice president, research, Foundation for AIDS Research, New York City;
Philip Keiser, M.D., professor, medicine, University of Texas Southwestern
Medical Center, Dallas; Feb. 22, 2007, New England Journal of Medicine
Last Updated: Feb. 21, 2007
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